In telecommunications, a femtocell-originally known as an Access Point Base Station—is a small cellular base station, typically designed for use in residential or small business environments. It connects to the service provider's network via broadband (such as DSL or cable). A femtocell allows service providers to extend service coverage indoors, especially where access would otherwise be limited or unavailable. The femtocell incorporates the functionality of a typical base station, but extends it to allow a simpler, self-contained deployment.
A Node B is an element of a 3G macro Radio Access Network (RAN), and a Home Node B (HNB) is the 3GPP's term for a 3G femtocell. Within an HNB Access Network there are two network elements: a HNB (or femtocell) and a Home Node B Gateway (HNB-GW). The HNB is connected to an existing residential broadband service and provides 3G radio coverage for 3G handsets within a home. The HNB Gateway is installed within an operator's network and aggregates traffic from a large number of HNBs back into an existing core service network.
Generally, a legacy wireless device communicates via a circuit-switched (CS) network. In the case of a HNB, a legacy CS wireless device communicates via CS techniques with the HNB access point. The HNB then communicates via the HNB-GW to provide access to the CS core, also referred to as the macro CS.
As mobile devices improve and include more enhanced capabilities, mobile devices have evolved to act as Internet Protocol (IP) devices. IP devices typically implement IP Multimedia services (IMS) sessions that utilize packet-switch (PS) communications instead of CS communications. Legacy CS devices, however, are unable to communicate with the PS network, and hence, the legacy CS devices are unable to utilize services or take advantage of the capabilities offered by IMS systems or other PS networks.
Thus, there is a need for a method and system that allows the legacy CS devices to utilize IMS services when communicating via a femtocell.